Re: :alnum: broken?

[Óscar Fuentes]

Mattias Engdegård <address@hidden> writes:

> 26 feb. 2020 kl. 23.38 skrev Eli Zaretskii <address@hidden>:
>
>> Please revert these changes.  I already said that I wasn't interested in 
>> making these regular expressions signal an error.
>
> Sorry Eli, I didn't realise it was a belief strongly held. The changes have 
> been reverted, of course.
>
> But perhaps you will let me attempt to sway your opinion? I was a bit
> lukewarm to the idea myself, but the irony was not lost on me after
> making this very mistake in the implementation of code designed to
> find regexp errors. In short, the check saves time for beginners and
> experienced users alike, with no downside worth speaking about at all.
>
> There is no way a byte-compiler warning could come close to the
> precision of a run-time check, and I speak with some modest experience
> on the subject. A compiler warning wouldn't have found my error, nor
> would it find common non-code use such as interactive search.
>
> Initially I was worried about someone's regexp-composing code falling
> victim of a more stringent check, but Paul convinced me that this is
> unlikely to be an actual concern. Besides, we do break absolute
> compatibility now and then for good reasons, and this is one. There is
> also GNU grep as a precedence.

Okay, I'll be the one who says it: make it optional, disabled as
default.

This will nullify any concern about backwards compatibility and make it
possible to test the feature on the field. Plus hopefully being useful
for some of those that know about its existence.